The present disclosure relates to systems and methods for providing artificial illumination, and more particularly, to systems and methods for simulating solar light.
Solar radiation, in the form of sunlight is difficult to simulate effectively on Earth because the sun functions as a point source but is a great distance from the surface of Earth, the light is generally modeled as unidirectional on earth. The photons of sunlight are collimated, with rays of sunlight parallel to one another. While this is not precisely accurate, the large size of the sun relative to the Earth and the great distance between the two makes it accurate for many circumstances. Because of these properties, it is difficult to simulate effectively solar energy over a large area with point-source or line-source lamps. Many tests of “solar” light are performed by using uncollimated light (for example, a spotlight) to approximate solar energy. However, because the light is not collimated and light photons impact the testing surface from any angle, test results may not effectively mimic what is seen in sunlight.
In order to simulate solar energy properly, light must be collimated through the use of various optics, such as lenses and mirrors. Further, sufficient light energy must be produced in order to mimic the intensity of solar energy across the entire illuminated field desired, with the light distributed evenly to provide adequate testing without “hot spots.”
The use of solar energy is becoming increasingly important to the energy-producing sectors, and the need for effective and efficient solar panels is similarly increasing. In order to establish the effectiveness, efficiency, and reliability of solar cells, there is a need for a strong, reliable, lightweight, and easily adaptable light source that simulates solar energy effectively with a reliable and predictable amount of useable light energy.
There is also increased interest in exploring the near-sun planets and the space around the sun itself. In order to explore these regions effectively, it is necessary to devise a testing apparatus that can effectively mimic the sun's power at various distances, in order to establish the reliability and effectiveness of materials designed to travel closer to the sun. Therefore, there is a need for a reliable apparatus that can mimic solar energy at higher concentrations than those found on earth.
In addition to developing future technology of solar collectors and spacecraft, an apparatus that effectively mimics high levels of solar light may find practical uses for already existing situations. By way of example, because cars, trucks, and other vehicles are exposed to sunlight for long periods of time, it is necessary to know how long the paint covering the body of the vehicle will remain effective and attractive.
One method of establishing the amount of damage to the paint is to expose a painted sample to the sun for a set duration or until fading has occurred. However, since most paint samples are expected to last for ten years or more, this is an inefficient method of testing. One alternative is to expose a painted surface to high levels of solar energy (e.g., equivalent to 20 suns) for a short period of time (e.g., about 6 months) to determine effectiveness over a longer period of time (e.g., about 10 years). Therefore, there is recognized a need in the art for a solar simulator that can provide high levels of solar energy for testing solar exposure.
In addition to providing solar energy, there is also a need in the art for an easily adaptable solar testing apparatus that can provide various configurations of light energy to a location. For example, it may be necessary to include a pure white light to a target, or to provide light having a reduced ultraviolent saturation, or an increased blue saturation. This demand may be due to testing requirements, variations in local sun color, or a desire to measure the effects of various color saturations on a surface. Therefore, there is a need in the art for a solar testing apparatus that has a widely configurable color palette.
One problem with current methods is that they require a large amount of light in order to approximate the sun. This is because the photons of the light from conventional sources, such as spotlights, are not directional like solar energy but impact the surface from a variety of angles, and therefore do not closely approximate solar radiation. Therefore, there a need in the art for a more efficient solar simulator that appropriately models solar energy.